On Fri, January 28, 2011 13:46, Andy wrote: > I did this to measure the shutter speed of my LF copal shutters. It worked > very well and has been useful a number of times. While the lens is in > spec, I measured almost a half stop error at the fastest shutter speeds. > It also showed that they become more repeatable after 3 or 4 practice > exposures. Such is life with old mechanical devices. > > the tricky part was to set the trigger on the o-scope and determining the > area under the curve as this is the only way to measure all of the light. Cut out along the trace, and weigh the bit you cut out. Another lovely lovely old trick for getting quite good approximations to things that are fairly hard to do with high precision. -- David Dyer-Bennet, dd-b@xxxxxxxx; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info
